1. Field of the Invention
The present invention relates to a gamma (.gamma.) correction circuit to be used, for example, with video camera or the like.
2. Related Background Art
Conventionally, a gamma correction curve used by a gamma correction circuit of a video camera is approximated by using a polygonal line which is realized by a diode circuit such as that shown in FIG. 1A. In this circuit, crossover points are determined by voltages E1 to E3, and the slopes of lines are determined by resistors R.sub.0 to R.sub.3. FIG. 1B shows the gamma correction characteristics realized by the circuit shown in FIG. 1A. I.sub.1 represents a current source, and D.sub.1 to D.sub.3 represent diodes.
The advantage is that this circuit is simple. However, it has a problem that unnecessary distortion is imparted to gamma-corrected signals because the frequency characteristics of the input level changes due to junction capacitance when the diode turns off.